标题： Nd$_2$PdSi$_3$中的长程磁相互作用以及中心对称金属中磁涡旋相的形成 显示英文标题

标题： Long-range magnetic interactions in Nd$_2$PdSi$_3$ and the formation of skyrmion phases in centrosymmetric metals

摘要： 我们对Nd$_2$PdSi$_3$进行了广泛的X射线和中子散射研究，这是Gd$_2$PdSi$_3$的一种同系化合物，最近发现其尽管具有中心对称的晶体结构，却能够容纳磁斯格明子晶格相。在整个布里渊区范围内测得了色散磁激发，并使用平均场随机相近似模型来确定Nd离子之间的磁相互作用。我们的分析表明，该系统中的磁相互作用延伸距离较大，并受到Pd和Si原子有序形成的晶体学超结构的显著影响。结果表明，这一类材料中磁斯格明子相形成的机制，例如Gd$_2$PdSi$_3$，是通过长程RKKY相互作用而非短程三角晶格的简并来实现的。 显示英文摘要

摘要： We present an extensive X-ray and neutron scattering study of the structure and magnetic excitations of Nd$_2$PdSi$_3$, a sister compound of Gd$_2$PdSi$_3$ which was recently found to host a skyrmion lattice phase despite its centrosymmetric crystal structure. Dispersive magnetic excitations were measured throughout the Brillouin zone and modelled using mean-field random-phase approximation to determine the magnetic interactions between Nd ions. Our analysis reveals that the magnetic interactions in this system extend over large distances and are significantly affected by a crystallographic superstructure formed by ordering of the Pd and Si atoms. The results suggest that the mechanism for the skyrmion phase formation in this family of materials, e.g. Gd$_2$PdSi$_3$ is through the long-range RKKY interactions rather than short-range triangular-lattice frustration.